Initial Vancomycin Taper for the Prevention of Recurrent Clostridium Difficile Infection

The first line therapy for an initial episode of CDI (Clostridium difficile infection) is 10-14 days of oral vancomycin which is now recommended over metronidazole in the 2018 guidelines from the Association of Medical Microbiologists and Infectious Diseases of Canada (AMMI). Although response rates for the treatment of a first episode of CDI now approach 90%, approximately 25% of patients who have a complete response will develop recurrence (rCDI) within 8 weeks. Doctors' ability to predict recurrence is evolving, but remains very limited. The investigators hypothesize that by extending initial vancomycin therapy with a 2-week tapering regimen this will reduce the risk of rCDI. Starting at the end of the initial 14 days of therapy, participants will be randomized to receive an additional 14-days of placebo or vancomycin taper (125 mg orally twice daily x 7 days followed by 125 mg orally once daily x 7 days). This taper was chosen as it represents two steps of a commonly used 4-week vancomycin taper. The investigators' proposal to evaluate the extension of initial treatment from 14 to 28 days with a tapering dose of vancomycin represents a practical clinical trial that capitalizes on oral vancomycin's safety profile, worldwide availability, and relatively low cost.